Hydrology & Hydrological Cycle -

HYDROLOGY AND HYDROLOGICAL CYCLE

Hydrology.

It is a science which concerns with the occurrence, distribution and movement of water.
It may also be define the science that deals with the depletion and replenishment of water sources.
When we say movement of water, it includes movement of water in atmosphere, on the surface of the earth, and below the surface of the earth.
In atmosphere, water is present in form of vapours. On surface of earth it is in form of rivers, lakes, ponds and snow etc.
Below the earth surface it is present in form of moist soils.
The water occurring below the surface of the earth is known as ground water.
Ground water occupies the voids of the soil.

Hydrological Cycle.

Except for the deep ground water, the total water supply of the earth remains in constant circulation between earth and atmosphere.
This water again falls over the earth in form of precipitation.
The part of precipitation again evaporates back to atmosphere, part is soake by the ground.
Rivers again join the oceans and evaporation of water again occurs from them.
The water that has percolated in to the ground either joins oceans or is brought to the surface by means of wells, infiltration gallerries etc.
So circulation of water from earth to atmosphere and back to earth is a continuous process.
It is this circulation of water or hydrological cycle, which keeps on using and then replenishing water.